Servo controlled piston pump?

[kdlklm]

I'm developing a machine that is driven with electronic joystick, and we want to use a servo controlled piston pump. The main reason is for the feedback from the servo to the joystick. But the problem is we can't find any pumps that aren't in the $3000 plus range.

My question is, does anyone know of any pumps that are a little more economical.

My other option is to use a manual controlled piston pump, with some sort of actuator. But we can't find one that will give any kind of feedback to the joystick. If there is something like this out there, it would be great.

 

[CJONE]

You really need to provide gpm and pressure requirements for a cost on pumps. Also control voltage. CJ

 

[kdlklm]

I realize that, but there's nothing in the price range that I'm looking for. The pump needs to be approximately 25 GPM @1500 PSI. Joystick voltage 9 to 32 Vdc.

 

[Duff]

What do you mean "Readback"?

If you function a joystick that sends a 10V signal to a Pulse Width Modulator, which then sends a 600mA signal to the servo for full stroke of the piston pump, it will not send a signal back to your joystick making it a little stiffer saying the loads getting heavier or we are now going faster.

However I think what you may be getting at is you want some type of smooth control over your hydraulics.

Unfortunatly when you are talking piston pumps and pilot controls systems you are talking money.

Instead of controling the piston pump with the joystick, why dont you control the valves.

For a cheap small piston pump, I would go looking at mini excavators that are being wrecked. Your taking a gamble on the pump, however its a tight budget.

For second hand servo control valves, I would try a ROV company like Oceaneering, Subsea7 or Fugro. If you get in the right ear of someone, you may do OK.

best of luck

Duff

 

[MHarryE]

Is this a one or two off or are you going to build several? 1500 psi is awful low for a piston pump. Lowest pressure one I used was at 3,000 psi but I think that was below the pump's rating. The pressure rating drives so much of the cost.

 

[kdlklm]

we are limited to a 30 hp motor, and the pump will be powering four drive motors. Right now the machine is just a prototype, but who knows what the future might hold for it.

 

[CJONE]

I realize that, but there's nothing in the price range that I'm looking for. The pump needs to be approximately 25 GPM @1500 PSI. Joystick voltage 9 to 32 Vdc.

How do you know about price??? When you say pump, why do you want to control pressure with a joy stick. Are you actually talking about a hydrostat and wanting to control direction?? CJ

 

[CJONE]

Is this a one or two off or are you going to build several? 1500 psi is awful low for a piston pump. Lowest pressure one I used was at 3,000 psi but I think that was below the pump's rating. The pressure rating drives so much of the cost.

A lot of lumber mills and industrial applications run at 1500 psi. You are right most all piston pumps are rated at 3k or better but high pressure stresses everything and it is better to run a lower pressures if you can. Mobile equipment has space limitation so they get HP by more pressure. CJ

 

[kdlklm]

It's going to be a four-wheel-drive utility vehicle. It's going to be driven by a joystick, which connects to a micro processor, which controls the servo on the pump. that will give us the forward and reverse motion. Were confident that 1500 PSI will be adequate for this application.

 

[CJONE]

It's going to be a four-wheel-drive utility vehicle. It's going to be driven by a joystick, which connects to a micro processor, which controls the servo on the pump. that will give us the forward and reverse motion. Were confident that 1500 PSI will be adequate for this application.

That is a hydrostat not a pump hence the $$$. You can use a piston pump with a 4 way proportioning valve. But it would be cheaper to use a small hydrostat at high pressure. What are you using for drive motors/motor? CJ

 

[kdlklm]

We are running 4 hydro-gear HGM - P Series motors. We want to make it as efficient as possible, that's why we want to use a piston pump.

 

[SSdoxie]

$3000 for electronic controlled pilot operated psiton pump is pretty good price IMO. These controllers on the pumps usually run 1/3 price of the pump. Be less expensive to use a pilot operated piston pump with a hydraulic servo control joystick.

 

[RickB]

We are running 4 hydro-gear HGM - P Series motors. We want to make it as efficient as possible, that's why we want to use a piston pump.

Hydrostatic transmission pumps are piston pumps with variable displacement via a movable swash plate. Pretty much what you are looking for by a different name and less the electronic control.

 

[CJONE]

We are running 4 hydro-gear HGM - P Series motors. We want to make it as efficient as possible, that's why we want to use a piston pump.

I'll see what I can do in the morning. I just wanted to be sure you were not going to put this unit in with a gear or charlynn type motor without filtration.CJ

 

[CJONE]

I'll also check on pilot operating the unit off of the charge pump unless you absolutly need electric. CJ

 

[kdlklm]

Unfortunately it needs to be electric, the controls need to be extremely sensitive, and very easy to move. Because of the nature the people that would be using it.

 

[CJONE]

Unfortunately it needs to be electric, the controls need to be extremely sensitive, and very easy to move. Because of the nature the people that would be using it.

The only units I can do would be 4-20 MA and 0-100 MA nothing in the 9-30V you are asking about. I am guessing you are going to run this at 2100 rpm. 3K is conservative for a new Hydrostat. CJ